packing
DATE：2022/3/29 9:14:54 / READ： / SOURCE：This station
packing
The purpose of filling is to reduce the cost of foam and improve the performance. There are many types of fillers, which should be selected according to need. Some fillers can enhance the effect, the principle is as follows. When the filler is added to the resin, the molecule of the resin and the molecule of the filler are mixed together, and there is a certain adhesion between them. When the adhesion force is large enough, the resin and the filler can cooperate to deform under the action of external force. In this case, the filler can play an enhanced role. Such as glass fiber as a filler in the resin, glass fiber filled with random staggered between resin molecular chains, if they have larger adhesion force between the resin molecule chain which mutual separation of glass fiber, resin molecules have the effect of the crosslinking, and the glass fiber resin also plays a similar role. Under the action of external force, the molecular chain of resin will bear the relative moving shear force between glass fibers, and its bearing capacity is related to the strength of resin itself, adhesion strength between resin and glass fibers, etc. Glass fiber and resin complex, under the bending, stretching and compression of external forces, due to the resin in the glass fiber between the transfer of stress, so that the glass fiber can jointly bear external forces, improve the total bearing capacity of foam plastics. In addition to improving strength, glass fiber resin can also improve thermal conductivity, improve thermal conductivity, so that the resin and glass fiber composite can reduce the tendency of local overheating deterioration, the performance of composite materials is often the synthesis of two kinds of material properties. This can improve performance. In addition also has joined fillers and resin adhesive is very poor, from the point of view of enhancement, it must be bad, but also has its special purpose, such as polyethylene film printing performance is poor, but add crushed glass powder, because the glass powder and poor adhesion of polyethylene, therefore when printed stretch film, make a tiny gap around the glass powder, The membrane uses these gaps to adsorb the dye. Adding this kind of filler to solve the difficulty that the film is not easy to print often makes the properties of the composite brittle.Here are some common fillers. Corrugated board equipment www.handern.com
Glass filler can be fibrous, can also be spherical, the former one is more used. Corrugated board equipment www.handern.com
1. Glass fiber as filler, generally cut into 6 ~ 12mm long, too long glass fiber in plastic processing molding is easy to intertwine into a group, resulting in uneven distribution. And it affects liquidity. Adding 20% ~ 40% glass fiber to ABS, PS, PA and PU can make products with increased strength, stable size and good cold resistance, which can compete with metal parts under certain conditions. For example, adding long 3 ~ 6mm glass fiber 20% in PE can increase the elastic modulus of PE by 2 times, increase the tensile strength by 1 ~ 2 times, increase the bending strength by 3 times, increase the thermal stability from 40℃ to 70℃, increase the flame retardant by 3 times, increase the rigidity by 2 ~ 4 times. But impact strength drops by 50% and creep by 30%. Similarly, fiberglass can also be used to strengthen thermosetting plastics, and can also be modified. For example, the heat resistance of phenolic plastics can be increased to more than 205℃ when fiberglass is added.
The effect of glass fiber on the properties of foam plastics is not exactly the same as that of unfoamed plastics. Taking rigid PU foam as an example, the amount and length of glass fiber have an effect on the physical and mechanical properties of the foam. Corrugated board equipment www.handern.com
2. Glass sphere or glass microsphere, diameter 6 ~ 50μm, hard and transparent. Using glass balls as fillers can reduce the stress concentration inside the resin, improve the flexural strength, tensile strength and compressive strength of the resin, improve the stability of the size, reduce shrinkage, improve friction resistance and fluidity. Hollow glass ball, ball diameter of 10 ~ 100μm, with it as filler can be directly made of low density products, its density up to 0.4g/cm? It has excellent properties such as heat insulation, noise attenuation, non - toxic, non - flammable and mildew proof. Corrugated board equipment www.handern.com
Calcium carbonate powder is often used as filler in foam plastics. Calcium carbonate is processed from natural limestone. According to different processing ways, calcium carbonate can be divided into two categories: one is directly ground into powder from natural limestone, the diameter of powder particles obtained by dry grinding is greater than 20gm, and the diameter of powder particles obtained by wet grinding is less than 20μm; The other is calcium carbonate obtained by precipitation, powder diameter of 0.05 ~ 10gm. Foam plastics often add calcium carbonate as an ingredient. Most of the use of wet grinding calcium carbonate and precipitated calcium carbonate, calcium carbonate because of a wide source, cheap, can also play a role of modification, is a more used filler. PVC plastic commonly used calcium carbonate filler, because of its low oil absorption, will not lose the formula of oil plasticizer. Adding calcium carbonate to epoxy resin plastics can reduce shrinkage, increase strength, improve heat resistance, reduce thermal expansion coefficient, reduce cost, its dosage can reach 50%. Adding calcium carbonate to polyolefin can improve hardness, creep performance and opacity. It is a common filler, and its dosage can be up to 30%. Calcium carbonate reacts chemically with acid. Too much calcium carbonate content in plastics will affect the viscoelasticity of the melt and affect the foaming ratio. Therefore, it is difficult to make high foaming plastics containing a large amount of calcium carbonate. Corrugated board equipment www.handern.com
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